Essay/Term paper: Enzymes

Essay, term paper, research paper:  Medicine

The structure of the enzyme is mainly dependent on the active site and variable groups. Extreme temperatures or extreme pHs
can alter the structure of an enzyme. Enzymes function to lower the activation energy to break the bonds. They achieve this by
putting stress and pressure on the bonds or creating a microenvironment for the substrate. Enzymes are regulated by inhibitors
or activators and can be inhibited by the products of the reaction, called feedback inhibition.

Enzymes are catalytic proteins; therefore they change the rate of a reaction without being consumed. This means that once and
enzyme does its job it can still perform the same function as it did before. Organic catalysts change the rate of a reaction
without being permanently changed. Enzymes are polypeptides that are made up of amino acids. Enzyme variable groups that
are exposed are the places in which biological processes take place. These side chains, commonly called "R groups," make up
the active site and catalyze the conversion of the substrate to make a product. These side chains are often called variable
groups because they are often what determines the kind of enzyme it is, therefore determining what substrates it will bond with.
A change in temperature or a fluctuation in pH can alter the enzyme"s structure. Anent temperature the alteration of the
enzymes occurs when the temperature is very high and the enzyme denatures and is unable to perform the desired task. The
temperature is so high that the active site of the enzyme changes and it is unable to bond with substrates. The pH at which
different enzymes denature differs from enzyme to enzyme. Similar to too high a temperature, if a specific enzyme is at a pH at
which the active site changes, the enzyme is unable to function. This illustrates how the structure of an enzyme is vital to its
proper functioning. Allosteric enzymes differ in structure than the previous enzymes addressed. The extreme temperature and
pH rules, however, still apply. Most allosteric enzymes are composed of two or more sub units, each having its own active site.
The allosteric enzymes are constantly changing between two conformational states, active and inactive states anent functioning.
This oscillation helps in the regulation of the enzymes.

Enzymes function as organic catalysts, meaning that they are organic molecules (proteins) that change the rate of reaction
without being consumed by the reaction. Enzymes form weak bonds substrates to break them apart or bring them together to
form bonds. The function of enzymes is to lower the energy (activation energy) required to break bonds. Bonds of substrates
are needed to be broken in order to make the products; this process requires energy to break the bonds. Enzymes speed up
the process of converting substrates to products by lowering the required energy. Enzymes lower this energy by putting
pressure on the bonds. The substrate induces the enzyme to slightly change its shape so that the active site fits more snugly
around the substrate; this induced fit brings chemical groups of the active site into strategic positions that enhance the enzyme"s
ability to perform its function of catalyzing the chemical reaction. Enzymes may also function by providing a microenvironment
for the substrate which a particular type of reaction. For example, near the active site of an enzyme there may be specific side
chains that aid in the transferring of specific elements to the substrate that are critical steps in catalyzing the reaction. Many
enzymes require cofactors, non-protein helpers, for catalytic activity. These cofactors may be bonded permanently bonded to
the active site or may bond loosely with the substrate. If the cofactor that aids in the functioning of the enzymes is an organic
molecule, it is more specifically called a coenzyme. Most vitamins are coenzymes or are raw materials of coenzymes; therefore
vitamins help in the functioning of enzymes.

The operation of each enzyme and metabolic pathway is tightly regulated, either by inhibitors or activators. Inhibitors can
covalently bond to the active site of enzymes, in which case the inhibition is irreversible, if the inhibitor is bonded with weak
bonds the inhibition is reversible. Competitive inhibitors compete for the active site of the enzyme, hence the name. These
inhibitors may resemble the enzyme and bind to the active site, blocking the substrate from bonding with the enzyme, thus
reducing the productivity or the enzymes. Noncompetitive inhibitors inhibit reactions to occur by binding to a part of the
enzyme other than the active site. The interaction of this inhibitor and the enzyme causes the enzyme to change its shape,
rendering the active site unable to receive substrates and make products. Allosteric enzymes also have specific ways to regulate
enzymatic functioning. While the allosteric enzymes oscillates from its active and inactive form inhibitors or activators may bond
to the allosteric sites. The binding of an activator to the allosteric site while the enzyme is in active form will allow the enzyme to
function, the binding of an inhibitor to the allosteric site while the enzyme is in the inactive form will impede the ability of the
enzyme to function. Cooperativity is when a substrate binds to the active site of an allosteric enzyme thus leaving the enzyme in
active form and aiding in the binding of other enzymes to the other active sites of the enzymes. Feedback inhibition occurs when
a metabolic pathway is turned off by the end product of the reaction. For example, the end product of a specific reaction may
be an allosteric inhibitor to the specific enzyme that makes the product; this prevents the enzyme to make more products when
they are not needed. As the product accumulates the product slows down the synthesis or products.



In conclusion, the structure of the enzyme is mainly dependent on the active site and variable groups. Extreme temperatures or extreme pHs can
alter the structure of an enzyme. Enzymes function to lower the activation energy to break the bonds. They achieve this by putting stress and
pressure on the bonds or creating a microenvironment for the substrate. Enzymes are regulated by inhibitors or activators and can be inhibited
by the products of the reaction, called feedback inhibition.